Re: Strange problem with low energy light bulb

[Arfa Daily]

But you can use a combination of red, green, and blue high intensity LEDs,
to create any variant of "white" that you prefer. From what Ive read so
far, the efficiency of the new high intensity LEDs is almost identical now
to that of CFLs, which means about the same lumens for 1/4 or 1/5th the
power of an equally bright incandescent bulb.

I think we shouldn't get stuck on any supposed problem with CFLs, as if
they are the only alternative here.

The weird thing about LEDs is that they would last such a long time that
they wouldn't need replacement. In principle, you can build them right
into the lamp itself. Or in walls, or whatever.

Bert

The length of service issue with LEDs is very dependant on the way they are
driven, if you are to get the maximum of 100,000 hours plus out of them.
However, that said, even if not driven properly - ie not pulsed - from what
I have read, they are still good for 40k hours, before the light output has
dropped by 50%. As far as colour rendering goes, I agree that this can be
achieved with combinations of RGB LEDs, and I'm sure can be made as good or
better now, as CFLs are ( not that I'm saying theat CFLs are good of course
.... !) Just a few days ago, I saw somewhere that one of the manufacturers
has come up with LED chips bonded to a sort of 'ball on a stick' shape, so
many small chips face in virtually every direction around a sphere, to get
over the point-source poor beamwidth issue.

BTW, Philips CFLs = China ? Not any more, it would seem. I picked one up in
the supermarket tonight to have a look. It said " Made in Poland " ...

Arfa

 

[Don Pearce]

The length of service issue with LEDs is very dependant on the way they are
driven, if you are to get the maximum of 100,000 hours plus out of them.
However, that said, even if not driven properly - ie not pulsed - from what
I have read, they are still good for 40k hours, before the light output has
dropped by 50%. As far as colour rendering goes, I agree that this can be
achieved with combinations of RGB LEDs, and I'm sure can be made as good or
better now, as CFLs are ( not that I'm saying theat CFLs are good of course
... !) Just a few days ago, I saw somewhere that one of the manufacturers
has come up with LED chips bonded to a sort of 'ball on a stick' shape, so
many small chips face in virtually every direction around a sphere, to get
over the point-source poor beamwidth issue.

BTW, Philips CFLs = China ? Not any more, it would seem. I picked one up in
the supermarket tonight to have a look. It said " Made in Poland " ...

Arfa

Currently, white LEDs are in fact blue LEDs coated with a fluorescent
substance, so probably the overall light quality will be quite similar
to CFL.

d

 

[Arfa Daily]

Currently, white LEDs are in fact blue LEDs coated with a fluorescent
substance, so probably the overall light quality will be quite similar
to CFL.

d

Hi Don

I just went looking at some of the latest LED technology, and they are now
producing LED chips that have an array of alternate red and blue die
'stripes', each made up of a string of individual dies, with the whole
overlaid with a yellow phosphor. By altering the colour of the phosphor,
they can set the colour temperature to any value they like and, it is
claimed, with a colour rendition index of 90 or better, so it seems that the
colour rendition issue with LED 'light bulbs' is a lot closer to being fully
resolved, than the 5 years that was postulated in one of the above posts. If
this is the case, and the field of LED lighting contnues to advance at the
pace that it has over the last say 3 years, then I would suggest that the
CFL has a very limited future ...

Arfa

Arfa

 

[Bob Urz]

Issues with LEDs today:

Color rendering
Diffusion

Once those are solved effectively, they will be excellent
alternatives. My guess is 5 years to color rendering, and 5 more to
diffusion. Most LEDs today filter a single color to a specific
monochromatic output. Even the LED-type flashlights are very heavily
skewed to the blue end of the spectrum in order to get sufficient
brightness, and require multiple LEDs to get even a minor beam with
very poor diffusion.

Peter Wieck
Wyncote, PA

http://members.shaw.ca/sagelighting/led_spotlights_and_bulbs_specifi.htm

http://www.electronicproducts.com/ShowPage.asp?Filename=hlap01.jun2006.html

http://www.californiagreensolutions.com/cgi-bin/gt/tpl.h,content=270

http://www.ledsmagazine.com/news/4/1/4

http://www.mew.co.jp/e-tecrepo/531e/main02.html
http://www.mew.co.jp/e/corp/news/2006/0603-01.htm

http://www.eetimes.com/showArticle.jhtml?articleID=181503227

Bob

 

[James Sweet]

Currently, white LEDs are in fact blue LEDs coated with a fluorescent
substance, so probably the overall light quality will be quite similar
to CFL.

It's not, the phosphor is not the same as used in a CFL, and the light
output is dominated by the blue from the LED chip. Another problem with them
is that they shift blue as the phosphor ages. They're improving, but still
far from perfect. There's a lot of Chinese crap LEDs on the market now too
that are noticeably inferior to good name brand ones. I had some bargain
white LEDs that got dim and blue after only about 2 months of continuous use
and that was driven below spec.

 

[Sal M. Onella]

Hell yes, and as we know that nature (allegedly) abhors a vaccuum, that
someone will really have to press the stuff in there hard. >

Only if Nature's got in there first.

 

[John Doe]

But you can use a combination of red, green, and blue high intensity
LEDs, to create any variant of "white" that you prefer. From what
Ive read so far, the efficiency of the new high intensity LEDs is
almost identical now to that of CFLs, which means about the same
lumens for 1/4 or 1/5th the power of an equally bright incandescent
bulb.

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.

The weird thing about LEDs is that they would last such a long time
that they wouldn't need replacement. In principle, you can build
them right into the lamp itself. Or in walls, or whatever.

Right, but pointless except for low light applications.

 

[Mr.T]

I've done a fair number of fairly large (i.e., 8 or more bulbs per room)
incadescent (mostly halogen) to CFL upgrades, with extremely positive
results. In every case the fixtures were previously loaded up with
incadescent bulbs rated at the fixture's maximum power. They were providing
poor to marginal lighting.

No argument from me that most halogens are even bigger crap than most CFL's.
However I had never assumed people do not bother to differentiate standard
filament light bulbs from small halogens.
I'm puzzled why they even bother to differentiate CFL's in that case. Simply
call them lamps

MrT.

 

[Mr.T]

Yes, when "you" make a choice... but this thread is not one comparing
CFL lamps to standard tube-types.

Taken literally THIS thread is NOT about lamps at all then. It is only about
"Stevenson = fucking moron".

However we all get to choose how we respond, you ONLY get to make your
choices NOT mine.
If you don't like it, simply move on to the next post/thread.

You may choose to argue on a
tangent, that is your privilege and absolute right.

Thank you.

MrT.

 

[Mr.T]

LOL !

You need to get out a bit.

Maybe you can tell us exactly which houses have electric lighting and 40degC
temperatures at night.
(or why they choose to run lights during the day in such conditions)
I obviously haven't been "getting out" to those!

MrT.

 

[Arfa Daily]

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.


Right, but pointless except for low light applications.

I have a friend who has LED downlighters as the only source of light in his
shop. They are perfectly bright and adequate for the job, if a little 'cold'
in colour temperature. Also, a local photography shop uses similar ones for
its window display, and again, the only comment you would make is that they
are a little cold. The specifications for up to date ones would certainly
suggest that they are on a par in terms of light output and beamwidth, with
comparable fitting halogens. With a bit of work, I'm sure that they will
also get to the point where they can replace a standard filament bulb, in
the same sized package, unlike a CFL which has to accommodate the ballast. I
think it might be a case of 'ya gets wot ya pay fer'

Arfa

 

[Lostgallifreyan]

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.

In your infinite wisdom, how do you explain this?

http://www.cree.com/products/xlamp.asp

NIST confim the brightness, so you don't have to believe the 'hype', you
only have to ask a few basic technical questions: How efficient is it?
Is there enough light to fit purpose at given cost?


"LED luminaires can only be considered high efficacy if the LED can be
tested (according to UL) to be at least 40 lm/W on the line voltage input
side of any power supply or other device.” Otherwise the fixture is not
considered high efficacy."
Source: http://www.icfi.com/Markets/Energy/doc_files/led-lighting.pdf


Light Type: lm/WW CRI Life (hrs)
Incandescent 17 100 3k
Halogen 20 100 10k
Cree XLamp 7090 XR 48 80 >50k
T12 flourescent 60 75-85 20k
Metal halide 70 70 20k
Cree XLamp 7090 XR-E 70 80 >50k
T8 flourescent 74 75-85 20k
High-pressure sodium 91 22 20k
Low-pressure sodium 120 5 18k
Source: http://www.cree.com/products/pdf/XLamp7090XR-Esheet.pdf

Even if you lose nearly half the light you can still claim high efficiency
to UL standards given the 95% efficient power converters made to run LED
lamps. It would be a poor luminaire that lost that much.

As for actual light output, newer LED's put out 176 lumens or more. That's
still a tad short of what's wanted in many cases, but not by much. 7 to 10
emitters would match a standard 100W incandescent (7 for the 240V type, 10
for the 110V type). Given that the cost of the first CFL's was around £26
in the UK, maybe £40 in todays money, that puts LED's in a good position,
you can get a lot better device for a lot less than that, even now, and
it's improving fast, a lot faster than the time CFL's took to develop, and
there are probably more ways to cut costs without sacrificing safety.

It would take only a fourfold increase in output from a single emitter at
same cost to make them compete with any other light source for domestic
use, and I think we'll only need to wait a few months for that.

 

[Arfa Daily]

In your infinite wisdom, how do you explain this?

http://www.cree.com/products/xlamp.asp

NIST confim the brightness, so you don't have to believe the 'hype', you
only have to ask a few basic technical questions: How efficient is it?
Is there enough light to fit purpose at given cost?


"LED luminaires can only be considered high efficacy if the LED can be
tested (according to UL) to be at least 40 lm/W on the line voltage input
side of any power supply or other device.” Otherwise the fixture is not
considered high efficacy."
Source: http://www.icfi.com/Markets/Energy/doc_files/led-lighting.pdf


Light Type: lm/WW CRI Life (hrs)
Incandescent 17 100 3k
Halogen 20 100 10k
Cree XLamp 7090 XR 48 80 >50k
T12 flourescent 60 75-85 20k
Metal halide 70 70 20k
Cree XLamp 7090 XR-E 70 80 >50k
T8 flourescent 74 75-85 20k
High-pressure sodium 91 22 20k
Low-pressure sodium 120 5 18k
Source: http://www.cree.com/products/pdf/XLamp7090XR-Esheet.pdf

Even if you lose nearly half the light you can still claim high efficiency
to UL standards given the 95% efficient power converters made to run LED
lamps. It would be a poor luminaire that lost that much.

As for actual light output, newer LED's put out 176 lumens or more. That's
still a tad short of what's wanted in many cases, but not by much. 7 to 10
emitters would match a standard 100W incandescent (7 for the 240V type, 10
for the 110V type). Given that the cost of the first CFL's was around £26
in the UK, maybe £40 in todays money, that puts LED's in a good position,
you can get a lot better device for a lot less than that, even now, and
it's improving fast, a lot faster than the time CFL's took to develop, and
there are probably more ways to cut costs without sacrificing safety.

It would take only a fourfold increase in output from a single emitter at
same cost to make them compete with any other light source for domestic
use, and I think we'll only need to wait a few months for that.

My feelings, too.

Arfa

 

[Eeyore]

"Eeyore" wrote


Maybe you can tell us exactly which houses have electric lighting and 40degC
temperatures at night.

I didn't say specifically at night.

There are plenty of tropical places where temps are that high. And there are
planty of ppor perolpe whi can't afford air conditioning in such places too.

Graham

 

[Eeyore]

I have a friend who has LED downlighters as the only source of light in his
shop. They are perfectly bright and adequate for the job, if a little 'cold'
in colour temperature. Also, a local photography shop uses similar ones for
its window display, and again, the only comment you would make is that they
are a little cold. The specifications for up to date ones would certainly
suggest that they are on a par in terms of light output and beamwidth, with
comparable fitting halogens. With a bit of work, I'm sure that they will
also get to the point where they can replace a standard filament bulb, in
the same sized package, unlike a CFL which has to accommodate the ballast. I
think it might be a case of 'ya gets wot ya pay fer'

The brightest LEDs do unfortunately have that cool blue 7000K or so colour temp.
There's a significant trade off in efficiency for the 3000K ones.

Graham

 

[Eeyore]

In your infinite wisdom, how do you explain this?

http://www.cree.com/products/xlamp.asp

NIST confim the brightness, so you don't have to believe the 'hype', you
only have to ask a few basic technical questions: How efficient is it?
Is there enough light to fit purpose at given cost?

"LED luminaires can only be considered high efficacy if the LED can be
tested (according to UL) to be at least 40 lm/W on the line voltage input
side of any power supply or other device.” Otherwise the fixture is not
considered high efficacy."
Source: http://www.icfi.com/Markets/Energy/doc_files/led-lighting.pdf

Light Type: lm/WW CRI Life (hrs)
Incandescent 17 100 3k
Halogen 20 100 10k
Cree XLamp 7090 XR 48 80 >50k
T12 flourescent 60 75-85 20k
Metal halide 70 70 20k
Cree XLamp 7090 XR-E 70 80 >50k
T8 flourescent 74 75-85 20k
High-pressure sodium 91 22 20k
Low-pressure sodium 120 5 18k
Source: http://www.cree.com/products/pdf/XLamp7090XR-Esheet.pdf

Even if you lose nearly half the light you can still claim high efficiency
to UL standards given the 95% efficient power converters made to run LED
lamps. It would be a poor luminaire that lost that much.

As for actual light output, newer LED's put out 176 lumens or more. That's
still a tad short of what's wanted in many cases, but not by much. 7 to 10
emitters would match a standard 100W incandescent (7 for the 240V type, 10
for the 110V type). Given that the cost of the first CFL's was around £26
in the UK, maybe £40 in todays money, that puts LED's in a good position,
you can get a lot better device for a lot less than that, even now, and
it's improving fast, a lot faster than the time CFL's took to develop, and
there are probably more ways to cut costs without sacrificing safety.

It would take only a fourfold increase in output from a single emitter at
same cost to make them compete with any other light source for domestic
use, and I think we'll only need to wait a few months for that.

I bet you'll find that LED has a 7000K or so colour temp. They're not very nice
for domestic lighting.

Graham

 

[Lostgallifreyan]

I bet you'll find that LED has a 7000K or so colour temp. They're not
very nice for domestic lighting.

True, I'm not wild about it, but so long as it can improve enough to avoid
sharp dips or peaks I don't mind some serious skew toward blue. We can get
used to it as we get used to changes in the colour of ambient daylight,
which is often close to what LED's already make. The sharper detail from
shortwave blues will help decrease fatigue and increase comfort when
reading or doing small-scale work. My only current beef with them is the
lack of nice rendering of reds. Adding some broadband red centred around
650 nm should fix that.

 

[Mr.T]

I didn't say specifically at night.

Then as I said, why do they use the lights during the day, rather than
operate some form of cooling?
IF they don't, your argument is totally irrelevant.

There are plenty of tropical places where temps are that high. And there are
planty of ppor perolpe whi can't afford air conditioning in such places

too.

And plenty who have no electric lighting either, but that has nothing to do
with the claim of 40degC ambient temperature at the light fitting when
operating.
Your whole argument is thus pointless. No real surprise there.

MrT.

 

[Eeyore]

And plenty who have no electric lighting either, but that has nothing to do
with the claim of 40degC ambient temperature at the light fitting when
operating.
Your whole argument is thus pointless.

Not at all. What kind of CFLs do you sell in tropical or desert countries ?

Graham

 

[Albert Manfredi]

Right, but pointless except for low light applications.

Suggest you do some searching here:

http://www.ieee.org/web/publications/xplore/index.html

Bert